Percussive tool valve



1936. H. J. SCHORLE ET AL 2,933,257

PERCUSSIVE TO OL VALVE Filed March 1, 1934 18 a 10 NH 9 INVENTORS A TORNEY Patented Mar. 10, 1936 UNITED TATES .PATENI OFFICE PERCUS SIVE TOOL VALVE ginia Application March 1, 1934, Serial No. 713,513

2 Claims.

more particularly for valves therefor.

An object of the invention is to provide a valve, simple in construction, light in weight, positive and light in action and one which will provide a heavy blow of the hammer piston of the tool and will cut down pressure fluid consumption in proportion to depth of hole drilled or work performed.

With these and other objects in view as may appear from the accompanying specification, the invention consists of various features of construction and combination of parts, which will be first described in connection with the accompanying drawing, showing percussive tool valves of the preferred form, and the features forming the invention will be specifically pointed out in the claims.

In the drawing:

Fig. 1 is a fragmentary longitudinal section through a percussive tool showing the valve in one position.

Fig. 2 is a view similar to Fig. 1 showing the valve in another position.

Fig. 3 is an enlarged section through the valve and valve chest.

Fi 4 is an isometric view of the valve.

Referring more particularly to the drawing, the improved percussive tool includes a cylinder I having a piston chamber 2 therein in which the piston 3 reciprocates. The hammer piston is reciprocated by air under pressure or similar pressure fluid, the distribution of which is controlled by the valve 5 for controlling the operation of the piston.

The rear end of the cylinder I of the percussive tool has a valve chest 6 positioned therein. A valve chamber 1 is formed in the valve chest 2 and has communication through a plurality of ports 8 with an annular channel 9 to which pressure fluid is delivered through the passage II) from any suitable supply. The initial delivery of pressure fluid to the percussive tool is controlled by a throttle valve I I of any preferred form.

The valve 5 comprises a cup-like body I 2 which reciprocates in the valve chamber 1 and has an annular flange I 4 formed thereon substantially midway of its ends. The flange I4 seats against the valve seat I5, as shown in Figs. 1 and 3 of the drawing, to out 01f delivery of pressure fluid through the passage I6 into the rear end of the piston chamber 2.

When the valve is positioned as shown in Figs. 1 and 3 of the drawing, the pressure fluid entering the valve chamber 1 through the ports 8 engages against the rear pressure area of the flange (Cl. 121-19) is invention relates to percussive tools and I4 and holds the valve seated against the valve seat I5. The pressure fluid leaks past the body of the valve 5 through the clearance space H and ports I8 into the annular channel I9 from which it passes through the ports 20 into the forward end of the piston chamber 2. At this time the piston 3 will be in its forward position as shown in Fig. 1 cutting off exhaust through the exhaust 2| and the pressure fluid entering the piston chamber 2 forwardly of the piston 3 will force the piston 3 rearwardly in the piston chamber on its return stroke and into the position as shown in Fig. 2 of the drawing. As the piston 3 moves rearwardly it uncovers the exhaust port 2| and. allows the pressure fluid to bleed or exhaust from the piston chamber 2 forwardly of the piston to the atmosphere, at the same time providing a pressure relief in the rearward side of the flange 5 and on the rim of the cup-like body I2. behind the flange I4 and the rim 22 of the cuplike body I2, the pressure fluid in the pressure space 23 formed in the cylinder, acting upon the forward side of the flange I4 together with the action of the compressed fluid or compression from the piston chamber against the pressure area 24 formed by the bottom of the cuplike body I2 will move the valve 5 into the position shown in Fig. 2 of the drawing.

Pressure fluid is delivered to the pressure space 23 through a. plurality of ports 25 which communicate with the ports 8 and with the space 23. There are substantially one-half as many ports 25 as there are ports 8 so that a pressure differential is provided between the pressure space 23 and the portion of the valve chamber I in which pressure fluid is provided for exerting pressure against the rearward side of the flange I4. This pressure difference permits a quick sharp action of the valve and. the delivery of a heavy blow of the piston 3 upon the forward or working stroke of the piston.

The inner surface 26 of the bottom of the cuplike body I2 forms a pressure surface opposed to the pressure surface 24. The pressure surface 26 is subjected to atmospheric pressure through a port 2'! in the stem 28. The port 21 has atmospheric communication through a plurality of transverse ports 29.

When the valve 5 is moved rearwardly into the position as shown in Fig. 2 of the drawing, delivery of pressure fluid through the ports I8 is cut off by the seating of the valve against the valve seat 30 and pressure fluid flows through the ports 25 pressure space 23 and through the Upon the relief of pressure clearance 3| and passage [6 into the rearward end of the piston chamber 2.

The greater volume of air in the pressure space of the valve chamber 1 rearwardly cf the flame l4 with respect to the volume of pressure air in the space 23, causes a'quicker closing of the valve and a quicker cut-off of the supply of pressure fluid to the rear end of the piston chamber 2 to save air which would otherwise blow out through the exhaust port 2| when the piston.

passes the exhaust port in its travel. It will also be clearly noted that the clearance space 3| is much greater than the clearance space H providing differential clearances on the body l2 on opposite sides of the valve M to permit more air to enter the rear end of the cylinder and cause the piston 3 to strike a heavy blow.

For returning the valve 5 to the position shown in Figs. 1 and 3 of the drawing the atmospheric pressure on the pressure area 26, and compression from the piston 2 acting upon the rim 22 of the cup-like body l2, will assist the pressure fluid acting upon the rear side of the valve M to throw the valve or move it into position to cut ofi the supply of pressure fluid to the rear of the cylinder.

It will be understood that the invention is not to be limited to the specific construction or arrangement of parts shown, but that these may be modified widely within the invention as defined by the claims.

What is claimed is:

1. In a percussive tool, the combination of a cylinder having a piston chamber, a piston in said chamber, an exhaust port in the cylinder, a valve chest having a valve chamber, inlet passages leading from said valve chamber to said piston chamber, a valve in said valve chamber comprising a. body, a flange on said body, valve seats formed on said chest, said flange engaging said seats to control delivery of pressure fluid to the forward and rear ends of the piston chamber, said chest provided with pressure fluid supply ports opening into the valve chamber, the ports for supplying pressure fluid to the rear of said piston chamber opening into the valve chest forwardly of said flange and the ports for supplying pressure fluid to the forward end of the piston chamber opening into the valve chamber rearwardly of the flange, the outer surface of said body being spaced from cooperating surfaces in the valve chest to form restricted passages for controlling the flow of pressure fluid, the clearance space on one side of said flange being greater than the clearance space on the other side of the flange for delivering a greater quantity of pressure fluid in a shorter space of time to one end of said Piston chamber.

2. In a percussive tool, the combination of a cylinder, a piston chamber therein, a piston in said chamber, an exhaust port in the cylinder, a valve chest having a valve chamber, inlet passages leading from the valve chamber to the piston chamber, a valve in said valve chamber and including a body having a rearward end and a bottom, a flange on said body, ports to supply pressure fluid to the opposite sides of the flange to throw the valve for supplying pressure fluid to said inlet passages, pressure fluid supply ports opening into the valve chamber, ports for supplying pressure fluid to the rear end of said piston chamber opening into the valve chest forwardly of said flange, ports for supplying pressure fluid to the forward ends of the piston chamber opening into the valve chamber rearwardly of the flange, the forward end of said valve body being subjected to compression from the cylinder to assist in throwing the valve in one direction, the rearward end of said body being subjected to compression from the cylinder and the inner Wall of the bottom of the body being subjected to atmospheric pressure to assist in throwing the valve in the opposite direction, the outer surface of said body being spaced from cooperating surfaces in the valve chest to form restrictions for controlling the flow of pressure fluid.

HERMAN J. SCHORLE. WILLIAM A. SMITH, JR. 

